Method of cleaning filters.



No. 819,358. v PATENTED MAY 1, 1906.

- J. MAGDOUGALL METHOD OF CLEANING FILTERS.

APPLICATION FILED APR. 5, 1900.

flamed 1%; V jrzwrziarz x State of Michigan,

new and useful Improvements inlllethods of UNITED} STATES ramw OFFICE,

JOHN UAcDOUGALL, OF .DE'IROIT; )IICHIGRIN, ASSIGNO'R, BY. DIRECT AND MESNE ASSIGNMENTS, T0 FRANK E. KIRBY, ()F DETROIT, MICHIUAN, Y

AND WILLIAM W. OF l\'lOI. I"REAL. CANADA.

' METHOD oF CLEANING-METERS,

To all who'm it may concern:

. Be it known that I, JOHN hIAGDOI'GAL-L,Of

Detroit, in the .count of Wayne and in the have invented certain CleaningF-ilters; and I do hereby declare that the-following. is a full,'clear, and exact ,descriptionthereof, reference being had to the acconipanyin drawing, in which 'the figure is a vertica section of a filter, in the cleaning of which my method may be .pr'aeticed.

The object of my invention is to provide a method of cleaning filters by which a minimum of water for washing will'be required; and to this end my invention consists in the method employed, substantially as hereinafter specified and claimed.-

For illustrating my inventlon'l-show a construction of filter such as appears in my a plication for United States patent filed l\' arch 16, 1900, Serial No. 9,306 3 but it is to be understood that this selection is merely for illustration oi the invention and is not to be' taken as restricting the scope thereof. Such filter com )rises a tank A, having an inlet-pipe B for the i ater to be filtered, which has a valve 1) and an outlet-pipe C for the filtered water, having a valve 0. Withinthe tank and resting u pen a suitable ialscbottom or support I) is a bed oi filtering material formed, preferably, of a top layer E of fine filtering sand, a second layer F of coarse sand,

and a third layer G of broken stone, which rests directly on the false bottom.

At the ecnter oi' the tank is a vertical pipe II, which extends through the filter-bed, and just above the latter has connected with it two oppositely-cxtendinghorizontal pipes I and I, which reach close to the. wall of the tank and each of which has in one side a slot or slots i and i. The pipe II at its lower end is in communication with. a pipe K, that passes through the bottom of the. tank and which has a valve /r. The pipes I and I have a pivotal connection with the pipe 11 to per? mit of their revolution around the tank, and for revolving them they aresccured toa Shall/.11 which receives motion from a suite able source of power.

Projecting downward from the pi es 1' and Specification of Letters Patent. I Applicationfiled April 5, 1900. Serial Nth-11,721-

Patented my 1, 1906.

whichit is befouled, which fingers by the revolution of the pipes'I and I agitate or-stir the be'fouled portion of the filter-bed.

In the operation of filtering the valves in' the inlet and outlet pipes are kept open and that in the pipe-K kept closed. when, however, thefilter requires cleaning because of the accumulation of matter in the filter-bed,

the valve 1) in the inlet-pipe B is closed to stop the influx of water. to the filter and the water in the-latter allowed tofilter out tllitll 'itreaches a level short distance above the pipes I- and I, and then thevalvc c in the out- The filter-bed is thenlet-pipe C is closed. agitated by the revolution of the stirring device to loosen up and dislodge the accumulated matters andto cause their comming ling with the body of water still present at or near and above the surface of the filter-bed, I

and when this treatment has been carried to the desired. degree, as evidenced by the conditiofi of such water, the valveic 1n the pipe -'K is opened to permit the dirty water'to flow ofi' througli the pipes I and I as they revolve,

andthenceflowing through the pipe K to some suitableplacc of discharge. Thus far it will'be seen no water has been re uired to be used in washing except the smal portion left in the filter, .as above described, and yet I alarge proportion of the sediment has been removed. Continuingthe process to complete the washing,filtered water by pumplngor otherwise is forced through the effluent-pipe .C or a pipe provided for the purpose back into the filter at such a rate as not to disturb the bed, but sufficient to carry such sediment as may still. be present up out of the same, where it can enter the pipesI ad I and thus flow with the. water out of the- 4; filter. During thiSIast-described operation the agitation of the filter-bed is kept up by the revolution of the pipes I- andI; but the rate at which the latter are moved is preferably much slower than during the-first stage of the process. Owing to the degree to which the cleaning is effected by the first part of the process, but a comparatively small portion of filtered or washwa-terv is required in the cleanin QPGHLUOIL have 'found that the fouling of filter-beds extends only partially therein, and hence that it is not necessary to agitate or stir the bedbelow the levelwhere it is befouled, and

that rceeuits, emi then passing accordingly I prefer to stir or eeitete only the betouled portion, elthou h (10 not of course restrict the scope or t e invention to the stirring of only a portion of the bed. .It is also preferable as conducirig to the most economical use of wesh'weter to remove the latter after Washing at a level comparatively close to su face of the filter-bed but I do not restrict myself to thie Heving thus described my invemion whet It elaim is-- I The n'iethoci cleaning filterbeds, which consists in agitating only the hefoulecl portion of the he'i in the presence of a fixed quantity of water, removing the dirty water pure water threughthe bed from the hot-tom upn'ard,

:l removiiig at or the bed sehstemtielly es earl. for the purdeecrihed.

2. The/method of eleeeine' fiiter-be is, which consists in agitating may the upper portion of the filter-bed in the presence of water before it has been filtered, removing ievei the surface the: betoulecl water which results, and then passing pure water uoword throu h the bed,

3. 'I hel-method of cleaning filter-beds, which coneists in agitating the upper portion of the filter-hed in the presence of a fixed quantityof water, removing the befouled water whiohresults, and then washing the bed by assing pure water therethrough from the ottom. upward.

1. The method of cleaning filter-beds, which consists in stopping the influx of water to he filtored.,-stopping its efl'lux when a predetermined level SLbOVB the bed is reached, agitating the upper iortiori of the bed only, removing the befou ed water which results, and then passing filtered Wa ter through the bed from the bottom upward.

In testimo's'yy that I claim the foregoing l, have hereunto set my heiirl this 5th day of April, A D. 1900.

- JOHN MACDQUGALL.

Witnesses JAS. E. I-lr rcmxeox, CHAS. J. lViLLm'ns'ox. 

